The present invention relates to static bars, which cause ionization of air to thereby generate ions.
Static bars and other static suppression or eliminating apparatus, also known as air ionizing apparatus, have been widely used. This apparatus provides a relatively high voltage to a sharp point, resulting in the ionization of air adjacent each sharp point in the apparatus. The ionized air is used to eliminate or suppress static electricity on dust, particles, electronic equipment, and sheets of non-conductive material, including paper and plastic, by way of example. Typically, a linearly extending bar is provided, having a plurality of ionizing points in line. Equipment used to provide alternating current to air ionizing apparatus is known as a "power unit," which is a specially constructed current limiting transformer which limits the flux in the secondary windings of the transformer. The "power unit" is usually supplied with alternating electric current from conventional mains which supply current at 120 volts. The secondary windings of the "power unit" operate at 4,000 to 7,000 volts, with very low maximum amperage in the secondary, in the order of five milliamps, due to the flux limiting construction of the "power unit."
Typically, the power unit is provided with an indicator light, which is intended to indicate that the static bar or other ionizing apparatus is "on", that is, that it is being supplied with electric current from a power source through the power unit and that it is functioning to ionize air. Although power units furnished with an indicator light have been widely used for many years, it has been found that the indicator light has given false information: although the indicator light is in the "on" condition, the ionizing apparatus may be essentially non-functioning.
As a consequence, users are misled into believing that the equipment for eliminating static electricity, such as static bars, is ineffective to perform its intended function, which often causes the shut-down of operating apparatus with which the static bars are used to suppress electricity, and causes other related problems.